Transistor forms RS 232C digital thermometerAn ordinary transistor can serve as an uncalibrated temperature sensor for an accurate, PC-compatible thermometer. Unadjusted accuracy is more than 0.5′C over the -50 to +50′C range, and the only limitation on resolution is the time devoted to measurement acquisition. For example, 0.1′C resolution requires less than 1 sec. The thermometer derives all its power from the RS-232C COM port.source